The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A020990 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A020990

a(n) = Sum_{k=0..n} (-1)^k*A020985(k).
(history; published version)

#40 by Joerg Arndt at Fri Oct 18 06:18:47 EDT 2024

STATUS

reviewed

approved

#39 by Michel Marcus at Fri Oct 18 05:44:48 EDT 2024

STATUS

proposed

reviewed

#38 by Paolo Xausa at Fri Oct 18 05:29:02 EDT 2024

STATUS

editing

proposed

#37 by Paolo Xausa at Fri Oct 18 05:28:31 EDT 2024

MATHEMATICA

Accumulate[Table[(-1)^n*RudinShapiro[n], {n, 0, 100}]] (* Paolo Xausa, Oct 18 2024 *)

STATUS

approved

editing

#36 by Michel Marcus at Sun Feb 12 03:12:41 EST 2023

STATUS

reviewed

approved

#35 by Joerg Arndt at Sun Feb 12 01:45:38 EST 2023

STATUS

proposed

reviewed

#34 by Chai Wah Wu at Sat Feb 11 23:34:31 EST 2023

STATUS

editing

proposed

#33 by Chai Wah Wu at Sat Feb 11 23:34:26 EST 2023

PROG

(Python)

def A020990(n): return sum(-1 if ((m&(m>>1)).bit_count()^m)&1 else 1 for m in range(n+1)) # Chai Wah Wu, Feb 11 2023

STATUS

approved

editing

#32 by Peter Luschny at Thu Feb 02 06:24:07 EST 2023

STATUS

reviewed

approved

#31 by Joerg Arndt at Thu Feb 02 05:09:40 EST 2023

STATUS

proposed

reviewed